This invention relates in general to machines for reducing materials and more particularly to ring hammers for such machines.
Most pulverizing, crushing, and shredding machines have massive rotors provided with hammers which impact against material introduced into the machine and reduce that material to a smaller size. In some machines the hammers are elongated bodies that pivot relative to the rotor at their inner ends and have enlarged heads at their outer ends for striking the material to be reduced. Other machines utilize rings that fit loosely around hammer pins on the rotor. The ring hammers are free to rotate relative to the rotor, and continually present different edges toward the material. Thus, they last considerably longer than swing hammers.
Ring hammers are manufactured in various configurations, with the specific configuration depending to a large measure on the nature of material that is to be reduced and the consistency that is desired in the final product. For example, where pulverizing to a high percentage of fines is desired, a plain ring should be used. On the other hand where cutting or shredding is desired, the ring hammers sould have teeth projected radially from them. Indeed, in certain instances it is desirable to have the teeth arranged in two circumferential rows to present as large a number of cutting edges as possible consistent with maintaining adequate strength (FIG. 1). Ring hammers of this configuration are ideally suited for reducing metal turnings to smaller sizes which are more easily shipped and for reducing lump coal to a size more suitable for use in stoker fed boilers and the like since few fines are produced. However, as the number of teeth increases, the teeth themselves become weaker and are more easily broken. Increasing the length of the teeth produces the same problem.